Back to Search
Start Over
Contribution of large-scale midlatitude disturbances to hourly precipitation extremes in the United States.
- Source :
- Climate Dynamics; Jan2019, Vol. 52 Issue 1/2, p197-208, 12p
- Publication Year :
- 2019
-
Abstract
- Midlatitude synoptic weather regimes account for a substantial portion of annual precipitation accumulation as well as multi-day precipitation extremes across parts of the United States (US). However, little attention has been devoted to understanding how synoptic-scale patterns contribute to hourly precipitation extremes. A majority of 1-h annual maximum precipitation (AMP) across the western US were found to be linked to two coherent midlatitude synoptic patterns: disturbances propagating along the jet stream, and cutoff upper-level lows. The influence of these two patterns on 1-h AMP varies geographically. Over 95% of 1-h AMP along the western coastal US were coincident with progressive midlatitude waves embedded within the jet stream, while over 30% of 1-h AMP across the interior western US were coincident with cutoff lows. Between 30-60% of 1-h AMP were coincident with the jet stream across the Ohio River Valley and southeastern US, whereas a a majority of 1-h AMP over the rest of central and eastern US were not found to be associated with either midlatitude synoptic features. Composite analyses for 1-h AMP days coincident to cutoff lows and jet stream show that an anomalous moisture flux and upper-level dynamics are responsible for initiating instability and setting up an environment conducive to 1-h AMP events. While hourly precipitation extremes are generally thought to be purely convective in nature, this study shows that large-scale dynamics and baroclinic disturbances may also contribute to precipitation extremes on sub-daily timescales. [ABSTRACT FROM AUTHOR]
- Subjects :
- METEOROLOGICAL precipitation
STREAMFLOW
JET streams
BAROCLINICITY
Subjects
Details
- Language :
- English
- ISSN :
- 09307575
- Volume :
- 52
- Issue :
- 1/2
- Database :
- Complementary Index
- Journal :
- Climate Dynamics
- Publication Type :
- Academic Journal
- Accession number :
- 135115090
- Full Text :
- https://doi.org/10.1007/s00382-018-4123-5